The present invention relates, in general, to scroll compressors which are used to compress a fluid, for example, a gas such as a refrigerant for cooling purposes or ambient air in order to furnish a compressed air supply.
More particularly, the present invention relates to an improved air inlet valve assembly for use in such a rotary scroll compressor.
So-called xe2x80x9cscrollxe2x80x9d compressors have achieved wider application recently, particularly in the fields of refrigeration and air conditioning, due to a number of advantages which they possess over reciprocating type compressors. Among these advantages are: low operating sound levels; reduction in xe2x80x9cwear partsxe2x80x9d such as compression valves, pistons, piston rings and cylinders (resulting in reduced maintenance); increased efficiency versus reciprocating compressor designs; and cooler operating temperatures.
While the number of wear parts in a scroll compressor may be reduced in comparison to a reciprocating type compressor, there are still a number of surfaces which move relative to one another and lubrication between these surfaces cannot be ignored. One design for a refrigerant scroll compressor utilizes an oil sump located in the lowermost portion of the compressor housing and an oil pump which draws oil from the sump upward to lubricate the moving parts of the compressor. The oil used as a lubricant in such a design is relatively free to mix with the air which is being compressed. Lubricating oil which becomes suspended in the refrigerant is, for the most part, separated therefrom by changing the direction of flow of the refrigerant and by impinging the refrigerant on surfaces located within the compressor. After it is separated, the oil is then drained back to the oil sump.
However, due to the gas having been relatively free to mix with the oil lubricant, the compressed gas exiting the scroll compressor may still have a relatively high degree of oil content. Such oil content may carry over to the compressed gas supply system and have deleterious effects such as reduced life of air driven mechanisms (e.g., air driven tools, brakes, etc.) which utilize the compressed gas supply as a power source.
One object of the present invention is the provision of a rotary scroll compressor which is xe2x80x9coilessxe2x80x9d in the sense that the lubricant used to lubricate the various moving parts of the compressor is not intermingled with the gas being compressed. Thus, there is no contamination to the compressed gas due to the lubricant, and additional special provisions or designs need not be utilized for separating the lubricant from the compressed gas prior to using the compressed gas.
Another object of the present invention is the provision of a novel and inventive air inlet valve assembly for a rotary scroll compressor which serves to provide gas to be compressed (e.g., ambient air) to the suction region of the compressor while preventing a backward rotation of the orbiting scroll element after the power to the orbiting drive mechanism has been terminated.
Yet another object of the present invention is the provision of such an air inlet valve assembly which is inexpensive to manufacture and reliable in operation.
In addition to the objects and advantages of the present invention described above, various other objects and advantages of the invention will become more readily apparent to those persons skilled in the relevant art from the following more detailed description of the invention, particularly when such description is taken in conjunction with the attached drawing Figures and with the appended claims.
In one aspect, the invention generally features an air inlet valve assembly for a scroll compressor, the scroll compressor including a housing, a stationary scroll element mounted within the housing substantially stationary with respect to the housing, the stationary scroll element including a stationary spiral flange, an orbiting scroll element disposed within the housing, each of the stationary and orbiting scroll elements having a central axis, the orbiting scroll element including an orbiting spiral flange, the stationary and orbiting spiral flanges being intermeshed and nested with one another to define a compression pocket therebetween, an orbital drive mechanism for driving the central axis of the orbiting scroll element in an orbit about the central axis of the stationary scroll element while maintaining the orbiting scroll element substantially non-rotational with respect to the stationary scroll element, and an air inlet channel connecting to the compression pocket for supplying air to be compressed to the compression pocket, the air inlet valve assembly including a valve piston positioned within the air inlet channel, the valve piston having a first position substantially blocking the air inlet channel and a second position substantially unblocking the air inlet channel.
In another aspect, the invention generally features an improvement in a rotary scroll compressor of the type described, the improvement including an improved air inlet valve assembly having a valve piston positioned with an air intake channel connecting to the suction region of the compressor, the valve piston having a first position blocking the air intake channel and a second position unblocking the air intake channel.
In yet another aspect, the invention generally features a scroll compressor including an air inlet valve assembly for supplying air to be compressed, including a housing, a stationary scroll element mounted within the housing substantially stationary with respect to the housing, the stationary scroll element including a stationary spiral flange, an orbiting scroll element disposed within the housing, the orbiting scroll element including an orbiting spiral flange, each of the stationary and orbiting scroll elements having a central axis, the stationary and orbiting spiral flanges being intermeshed and nested with one another to define a compression pocket therebetween, an orbital drive mechanism for driving the central axis of the orbiting scroll element in an orbit about the central axis of the stationary scroll element while maintaining the orbiting scroll element substantially non-rotational with respect to the stationary scroll element and an air inlet channel provided through the housing, the air inlet channel connecting to the compression pocket and the air inlet valve assembly being for supplying air to be compressed to the compression pocket, the air inlet valve assembly including a valve piston positioned within the air inlet channel, the valve piston having a first position substantially blocking the air inlet channel and a second position substantially unblocking the air inlet channel.